Intramolecular Carbolithiation of Allylo-Lithioaryl Ethers: A New Enantioselective Synthesis of Functionalized 2,3-Dihydrobenzofurans
作者:José Barluenga、Francisco J. Fañanás、Roberto Sanz、César Marcos
DOI:10.1002/chem.200500377
日期:2005.9.5
A new and easy method for the diastereoselective synthesis of 3-functionalized 2,3-dihydrobenzofuran derivatives from allyl 2-bromoaryl ethers is described. The key step of this transformation involves an intramolecular carbolithiation reaction of allyl 2-lithioaryl ethers. The substituents in both the allyl and the aryl moieties play an important and decisive role in stopping the reaction at the benzofuran
描述了一种从烯丙基2-溴芳基醚非对映选择性合成3-官能化的2,3-二氢苯并呋喃衍生物的新方法。该转化的关键步骤涉及烯丙基2-锂硫代芳基醚的分子内碳锂化反应。烯丙基和芳基部分中的取代基在终止在苯并呋喃处的反应中起着重要的决定性作用,从而避免了γ-消除反应。最后,该方法适合于通过使用(-)-天冬氨酸作为手性诱导剂来合成对映体富集的化合物。